Green Eyed Theory
by Madartiste
Summary: Lucy tests a theory - and Natsu's limits. (Nalu oneshot)


_**Summary: **__Lucy tests a theory - and Natsu's limits.  
__**Author's Notes: **__Oh lord, this one got away from me. I was just playing around with the "Lucy tries to make Natsu jealous" trope and things happened. This gets a bit… gropey, I'm going to say. Nothing too explicit, but more than normal and I can't say I'm all that good at it. Small spoiler for GMG arc._

* * *

Sitting on an overturned crate, Natsu narrowed his eyes at the sight of his partner. Their job had been relatively easy, but predictably explosive. There were piles of unconscious thugs laying about waiting for the authorities to finish processing their fellows. The section of the town where the Fairy Tail mages had encountered the gang was still smouldering in a few places with smashed windows and caved in walls.

All in all, it hadn't been THAT bad. Even Lucy didn't throw as much of a fit as she normally did since the person who had contracted them admitted they expected a certain amount of collateral damage. This particular group of bandits were known for wrecking things, and Erza was already conversing with the town's law enforcement to clear up any questions about what happened.

No, the potential repair bill was definitely not what was disturbing the fire dragon slayer. It was Lucy. Or more precisely, the man who was currently leaning in close and making her smile.

"Hey, Gray?"

"Yeah, flamebrain?"

Natsu didn't even react to the insulting nickname, such was his focus. "Why do I want to punch that guy in the face?"

"You mean that guy?" The ice make mage jerked a thumb to indicate the tall, dark and handsome son of the man who had hired the Fairy Tail wizards. The wealthy "pillar of the community" had been extremely concerned about the brigands who were harassing the townspeople and even put a good amount of his own money up in order to get them cleared out. His son had immediately been taken with the blond celestial wizard and attempted to strike up a friendship.

Gritting his teeth when Lucy laughed at something the interloper said, Natsu nodded. "Yeah. THAT guy."

Gray considered the situation for a moment, studying the other brunette from a distance. "If you were anyone else, I'd say it's because he's chatting up Lucy." His eyebrows shot up when the man reached out to tuck a loose strand of blond hair behind the girl's ear. "Damn. He moves fast."

The fire wizard's jaw clenched so hard it made him see stars. "What's so great about him, anyway? So what if he's rich and smart… and likes to read… and…" He scowled, not wanting to think about just how much this stranger seemed to have in common with his partner. Watching the two of them talk about their education and privileged upbringings had made him annoyed from the start.

"You left out tall and good looking," Gray snickered. "So I guess you DO get jealous, huh?"

"Why would I be jealous?!" Natsu gestured towards the scene with an angry swing of his hand. "I could break that guy in two with just my pinky." He slouched in a sulk. "He's not even a wizard."

"He really seemed to connect with her, though." Glancing at his teammate, Gray actually felt a bit bad for teasing him. It was obvious that Natsu hadn't come to terms with whatever feelings he had for Lucy, but it was still eating at the pink haired lunatic. "Look, I don't think you have anything to worry about. Did you see how she moved back when he touched her? That's a pretty clear sign he stepped over the line."

Perking up, the fire dragon slayer _did_ notice that there was more distance between the two than there had been. Lucy's smile had also taken on a more 'polite' edge rather than the truly pleased one he preferred to see on her face. She glanced in Natsu's direction, and the smile he'd been studying warmed up for just that split second their eyes met. He felt that weird twang in his gut that only seemed to happen when Lucy was involved. "Feh. I'm not worried. I could take him."

"Riiiiight," Gray drawled. "Because that's what this is about."

"Natsu!" The two male mages looked up to see Erza still standing with the officer, crooking her finger in summons for the pink haired boy.

"Aww crap," the fire wizard muttered, pushing off the crate he'd been sitting on and loping over to the redhead in the distance. No way this was going to be good for him.

They were too far away for Gray to make out their words, but he laughed when the armored woman smacked Natsu upside the head. She pointed to a building with a substantial hole in it's side and glared furiously. In response, the dragon slayer ducked his head and scuffed a sandal in the dirt with a rueful expression.

"I hope Erza's not too mad," Lucy said. She'd managed to disengage herself from the fawning wealthy scion, hustling over to Gray with an excuse that she needed to speak to him. Not that the blonde didn't appreciate all the attention he'd been giving her, but...

Chuckling again, the ice mage wizard shook his head. "Nah. She only whacked him one. If she was pissed, she probably would've slugged him." He shifted his head to shoot the girl a speculative look. "Did you finally decide you'd had enough of that guy?"

She sighed, taking Natsu's former seat on the wooden box. "He's really nice, but a bit too… Ugh, I dunno."

"And here I thought it was love at first sight," Gray said, smirking.

She cast him a wry smile and shook her head. "Not even close. I left that kind of rich life behind for a reason, and he's really a product of it."

"Probably for the best," he commented and got a questioning look in return. "Natsu was starting to get a little… resentful of all the attention that guy was giving you."

Frowning, Lucy cocked her head. "What? All he did since we got here was complain that he couldn't go right out and fight these guys. He didn't even seem to notice."

"That's all he said to you, maybe. But he just told me he wanted to punch out your admirer there." He shrugged one shoulder and then grimaced when he realized his shirt had gone missing. Where…? Oh, forget it. "He seemed pretty jealous to me."

"Jealous?" Her short laugh was scoffing, but her face looked thoughtful. "Really? I didn't think he cared about that sort of thing…"

Gray rolled his eyes. Sometimes it got exhausting being around those two and their weird little maybe-almost-romance dance. He moved to stuff his hands into his pockets and encountered the material of his boxers instead. "God damnit! Where did my pants go?!"

With a put-upon sigh, Lucy stood up and brushed at some dust on her skirt. "Here. I'll help you look. I'd rather not see Erza blow a gasket because you lost your clothes again."

Setting out to track down the wayward trousers, she couldn't help but consider Gray's words. Her first instinct was to blow them off, but lately the fire dragon slayer had been acting oddly towards her…

Maybe it was time to test a theory.

* * *

Natsu scowled and tapped his foot impatiently. Was she going to get stopped by every dude on the street? All week guys had been fawning over Lucy wherever they went. It wasn't unusual for the blonde to attract appreciative male gazes, but normally she just politely put them off. For some reason she'd been strangely gracious and talked to EVERY. SINGLE. ONE. of them. The whole damn week.

When she hid another giggle behind a coy hand and the creep leaned in closer, the dragon slayer's patience snapped like a rubber band. Stalking forward and seizing his partner by the wrist, Natsu bared his teeth at the quickly cowed stranger before pulling the girl along behind him.

"Geez!" Lucy huffed. "I wasn't taking THAT long."

He ignored her protests, jaw set and brows lowered, as he dragged her towards the guild hall. Really, she hadn't delayed them that much, but his frustrations had been piling up ever since they returned from their last mission. Her friendliness with each male to cross her path had grated every last one of his nerves raw.

To make matters worse, Lucy had been extra affectionate with him too. Dressing nicely, leaning on him, smiling that freakin' smile of hers that made his stomach feel like the floor was dropping out from under him… She'd just smelled so damned good when she curled up against him on her couch last night that he'd been a bit terrified of his own reaction.

There was also the fact he was pretty certain Lucy had felt his hard on when she'd leaned over his lap to grab her book. The saucy little smirk she'd thrown his way hadn't helped the situation. He'd been running full tilt in a state of hyper awareness for days now, and he was having trouble grasping exactly why.

Well, that wasn't ENTIRELY true. He did have _some_ idea why.

You couldn't grow up in a guild like Fairy Tail and _not_ learn more than you were comfortable knowing about sex, and Igneel had taught him the basic biology behind the whole thing. It also wasn't as if he'd never noticed Lucy's feminine assets before, either. Saying he'd been okay with seeing her naked was like saying Happy kinda liked fish - and understatement if there ever was one. But he'd never been so… consumed by his own body's reaction to her before. Was it because _she_ was instigating it this time? It was unbearable!

Natsu pulled up short when Lucy dug in her heels. She tugged on her arm with a peeved look until he finally let go. "I know how to get to the guild. You don't have to carry me there."

"Maybe I should!" he snapped. "At least you would be stopping to talk to every jerk who looks at you!" As soon as the words were out he felt a stab of regret and irritation. The dragon slayer ran one of his palms down his face, but was surprised when Lucy wrapped her fingers around his other bicep instead of yelling at him.

"Then why don't you escort me properly instead?"

Whatever that strange, calculating look in her brown eyes was made his blood feel like it was burning. She shifted closer, chest brushing his arm. He was pretty sure he would just explode in a fireball right there.

Natsu's dark eyes automatically dropped to the point where her breasts were in contact with his limb, and he viciously cursed whatever part of his brain had made him think groping her boobs when she'd been flung against him naked back in Crocus was a good idea. He knew what those delightful, heavy mounds felt like underneath his questing fingers, and right now he really wanted to-

He choked on his own saliva and skittered away. This was seriously bad. "Wha… W-We should…"

Face intense, Lucy closed the distance again. "We should what?" She took another step and had to tilt her chin up to look into his face. They were so close he could feel her breath ghosting along his jaw, and he swallowed hard. Her voice was husky and oh so warm. "What do you want, Natsu?"

A high pitched, animalistic whine came from the dragon slayer, and he took off at a brisk walking pace. "We should get there before all the good jobs are taken!" he called, not looking back.

"Uh huh," Lucy muttered to herself, feeling rather satisfied. "That's just what I thought."

Despite his words, Natsu was sitting at the bar stuffing his face with flaming chicken by the time she caught up with him. His eyes flickered to her and then back to the food. Mira smiled brightly at the celestial wizard. "Good morning, Lucy. How're you today?"

"Oh, I'm great! It's been a wonderful week so far," Lucy cooed, sitting down on the stool next to her pink haired teammate. "I've had four guys ask me out on dates."

Mira looked surprised, and Natsu bent over to gnaw on his poultry with more vigor. The barmaid glanced at him briefly. "Well, that's quite nice. Where are they taking you?"

Setting her elbow on the bar, Lucy propped her chin up with her fist. She had her head turned so she could watch Natsu's furious feasting. "I turned them down. I wasn't interested in any of _them_." He stopped cold with the fork still in his mouth when she reached out to skim a fingertip along his tense arm.

"Really now?" Catching on quickly, Mira studied the pair. "That's a shame, but maybe it's for the best. Natsu?" He glanced up questioningly, forcing himself to chew and swallow. "Would you like some more?"

"Uh… No, thanks. I'm… gonna see what missions there are." Laying the fork down on the now empty plate with a hasty clatter, the dragon slayer stood and scuttled over to the job board.

Lucy shifted her eyes to look at the take over mage, smirking. "Mmmm hmmm."

"Oh my…" Mira giggled. "I wonder what _ever_ could have Natsu so hot and bothered. I've never seen his face so red."

Examining the nails of her free hand, the celestial wizard blithely said, "Not a clue. But I've pretty much confirmed my theory."

"Don't push him too hard, now. Natsu doesn't always react well when people he cares about suddenly start acting different."

"I know." Lucy looked a bit chagrined. "And now that I'm sure, I'll stop. It's just so hard to tell what he's thinking sometimes that I couldn't help myself. You wouldn't expect a guy like that to bother hiding any of his feelings."

The eldest Strauss nodded. "He can be surprisingly complicated."

Blowing out a breath that ruffled her bangs, Lucy drummed her fingers on the bartop. "The only problem I have is… what do I do now that I know? I guess he's attracted to me physically but…" She broke off the thought when Natsu started back in their direction. He was scowling. "Nothing good, huh?"

"No, just a bunch of boring stuff." The boy fidgeted, eyes darting around the common area like he was afraid to make eye contact. "Happy won't be back till tomorrow from his job with Carla and Wendy anyway."

Lucy slapped her palms lightly against the bar and pushed herself to her feet. "Alright, then. How 'bout we go clean your house instead?" She really _did_ feel guilty about winding him up so much, and this was the best way she could think to make amends. "Happy was complaining about some kind of funky smell in your kitchen before he left."

Natsu eyed her with a shuttered expression, not sure if he should be wary or elated. The male part of his brain was giddy at the thought of having her all over him in his den, but he had serious doubts that he could keep his cool if that happened. Her smile was one of those genuine Lucy smiles, though, and he relaxed. "Yeah, sure. I guess that would be fine."

Deep into the afternoon the fire wizard was contemplating how he kept making unexpectedly terrible decisions regarding his partner. He was exhausted after being bossed around and made to wash every inch of his own home. Everytime he thought he was finished, Lucy directed him on to the next location. The girl had been so tireless in her reorganizing and dusting that he seriously wondered how she got worn out just walking to places for missions. There had been one other crucial thing that he'd overlooked too.

His entire house now smelled like Lucy.

She'd put her hands on everything. Rearranged his momentos, folded his clothes, washed his pillows… The last one was going to be a problem, he belatedly realized. He had no idea how he was supposed to sleep with Lucy's scent infecting his nostrils and making him think…. things. _Naughty_ things.

At first he'd been relieved that the girl wasn't hanging off him and brushing body parts against his, but Natsu slowly came to the realization that Lucy keeping her distance was just as bad. Even when she wasn't trying, he still found himself staring at her bouncing chest as she bent over to scrub at a stain and her firm backside when she rose up on her toes to dust his kitchen cabinets. He felt like someone was plucking strings in his guts.

He'd turned into a hormonal pervert! What had she done to him?

Lucy was completely unaware, humming as she strolled on her way home through the streets streaked with orange light. Natsu had insisted on taking her back to her apartment since the sun was already setting, but he found he was getting turned on just watching the back and forth sway of her hips as he lagged behind. He really, really wanted to reach out and grab that beautifully shaped -

"Lucy!" She spun slightly at the sound of name and smiled amiably at a handsome, brown haired man that was jogging towards her. "Hey, I just wanted to talk to you again." The girl no longer had the overly flirty mannerisms that had been driving Natsu to distraction, but the other guy didn't seem to care. "I know you said you were busy tomorrow, but I thought maybe we could get together this weekend?"

"That's really sweet, Terence, but I don't think I can make it." Her smile stretched slightly into an apologetic grimace.

Not willing to give in, the brunette stepped in close. "Well there has to be some time we can have dinner. You and I have so much in common. It would really be a shame -"

"No, I really can't. Thank you, though." He reached out when Lucy withdrew, gripping her upper arm.

The way his fingers dug into the celestial wizard's flesh and the tiny pained noise they pulled from her made a rage filled bubble pop inside Natsu's brain. He suddenly found himself standing over Terence's prone form without having realized he'd moved. The dragon slayer's fangs were bared in a savage show of teeth, and his knuckles had the telltale sting of having struck someone's face.

There was also the fact that Terence was rolling around on the ground clutching his bleeding nose. "Yer crazy!" he whimpered through his fingers.

"She said no," Natsu snarled. "Even I know that means to _back off_." He jerked in surprise when Lucy put tentative hands on his arm. The dragon slayer grabbed her wrist, careful not to grip too hard, and stalked off with the girl in tow.

She let him drag her down a few alleyways in an alternate route to her home before she finally said, "I _do_ appreciate you protecting me, but I think you over reacted -"

Spinning around, he faced her with bottomless dark eyes. Natsu was seething, nostrils flaring with each short, sharp breath in and out through his nose. The weird adrenaline surge from his very brief encounter with Terence was making him jittery and twanging at his instincts. He didn't even know why he'd been so _angry_. Lucy could thrash some dirt bag like that herself, but he'd just _snapped_.

The girl studied him carefully, a soft frown tugging down the corners of her mouth. She took a step towards him, and he tensed. "Are you okay?"

"Yeah," he grit out. "Fine."

Raising a hand, she laid her cool, smooth palm against his cheek, and his shaky exhalation warmed the inside of her wrist. Tension radiated through his body, vibrating in all of his muscles. Lucy wasn't sure what she was going to say to him when her lips parted, so nothing came out. His eyes dropped to stare at her open mouth, and when she licked her lips while she tried to collect her thoughts he felt some thread inside him abruptly break. It felt like a dam bursting.

Natsu seized her face in both hands, driving her backwards until she connected with a brick wall. His mouth sealed over hers as he laid himself flush against the celestial wizard, needing to feel every part of her at once. A small noise of surprise squeaked out of the corner of her mouth, but she didn't push back.

The bit of his brain that wasn't overwhelmed screamed that he was completely out of line and making a terrible, terrible mistake. It went completely silent, though, when she opened her lips to him and wound her fingers into his hair. The blazing blood in his body slithered down to pool low in his belly, abandoning his brain for more exciting areas, and he moaned loudly as Lucy's tongue tangled inelegantly with his. He had no idea what he was doing but couldn't stop if he wanted to.

Natsu pressed himself even closer, and was rewarded when Lucy spread her thighs farther so he could stand between them. The most delicious, provocative scent he'd ever encountered slammed into his nose like a punch from Gildarts. It was sweet and thick, coating his nasal passages and rolling down the back of his throat. He could almost _taste_ it, and a bone deep shudder wracked through his body. It was the most _Lucy_ thing he'd ever smelled. And, oh, did he want more.

Feeling swept away by the desire raging through his body, the dragon slayer started to pull back. The last the he wanted was to lose control and hurt someone so precious to him. But her fingers tightened in his pink locks, pulling hard enough to sting, and he growled into the inviting wet cavern of her mouth. The pain caused by her nails in his scalp just seemed to fuel the wildfire consuming his veins.

He forcibly ripped his mouth from hers so he could latch on to her jaw, sucking and licking his way to the tender space behind her ear and then down her neck. The succulent taste of her skin was enough to tear any coherent thoughts from his fogged mind. Her mewling affirmations drove a spike of lust right into his groin, making him involuntarily rock his pelvis against hers in a search for relief. The friction was like an explosion of searing pleasure going off in the most sensitive part of his body.

Lucy gasped and clawed at the back of his head and shoulders, encouraging him to keep going with little stuttering bumps of her hips. The hard, hot bulge of his erection hit in just the right spot, driving her sudden hunger for him. The fire dragon slayer's blazing hands shifted down to grasp at her breasts, kneading desperately into the pliant flesh that had been taunting him for days. His passionate groan echoed in the abandoned ally, and she could feel it vibrate along her clavicle where his lips were teasing.

Feeling feverish and frenzied in her desire for more contact, the celestial wizard raised her thigh and hooked her ankle around the back of his knee. The action tore a snarl from deep in his chest as the maddening smell of her arousal increased, and he thrust his hips against hers almost violently before suddenly going still. She could feel him shaking from the effort of restraining himself, fingers still digging into her bosom.

With exquisite care, he untangled himself from Lucy, gently sliding her leg back to the ground. He didn't meet her eyes as he took a good number of steps back, body tense as a wire. "Natsu?" she whispered, wondering if she'd done something wrong.

He flinched, hunching his shoulders a little and scrubbing at his face with his palms. "Shit, Lucy… Damn it… I'm sorry."

Surprised by his apology, she reached out a hand but stopped short of touching him. "For what? Did I seem like I was resisting there?"

Natsu snorted and pressed the heels of his hands into his eye sockets briefly. "No… But I didn't exactly ask you if it was okay." He let his hands drop, slapping bonelessly against his thighs.

She closed her eyes for a second, trying to will the buzzing of her nerves to calm. Blowing a long sigh through her nose, Lucy said, "If anyone should be apologizing, it's me. I kept after you all week."

He glanced at her, seeming weary and worn after their delirious almost-tryst. "Why _did _you do that?"

"I… wanted to know," she admitted, feeling foolish now that it was being put into words. "I wanted to know if you really were attracted to me. After how you've been acting lately..."

"Fuck," Natsu muttered with a grimace. "You couldn't just ask me? That was like some kind of torture. I thought you were trying to punish me."

"You really would've told me if I asked?" she demanded. Pushing off from the wall, Lucy moved a bit closer. His sheepish look and anxious tug on his scarf was more than enough answer to her question. "That's what I figured. Is it that hard to say? Is it something wrong with me?"

"No!" he blurted and then scowled. "It's not you. I… just…"

"Just what? Spit it out!" Lucy's thwarted hormones were making her really short tempered, and she planted her fists on her hips.

Natsu sagged, tipping his head so he was looking at her out of the corner of his dark eyes. "I'm… not ready."

Well, _that_ took the wind out of her sails. "Oh," she said. Now Lucy just felt terrible. What kind of friend was she to do this to him? The guilt made her previous fervor evaporate into the evening air.

Kicking at a piece of gravel so it ricocheted off the wall and down the now darkening alley, the fire wizard grunted. "I'm not good with change, Lucy. Never have been. I just never know how to handle it, and this… is a pretty big change."

"I'm really sorry. I shouldn't have pushed you like that." The celestial wizard was starting to consider calling Virgo so she could have a hole to crawl into for a few months. She seriously felt awful.

"Yeah, well, if you hadn't pushed I probably just would've ignored it forever," he muttered, rubbing at the back of his pink head. "Besides, it's not like I didn't enjoy it. I never cared about any of this touchy feely romance stuff before, but you… you..." Looking up through his lashes, Lucy could see the banked flames of lust still flickering in the fathomless depths. "I… want you," he breathed heatedly.

"Wow," she whispered. That scorching gaze wound the coil in her belly right back up, and she only felt a touch of embarrassment when she responded, "I guess... I want you too."

Natsu shivered at her plainly spoken words. "Will you wait for me? I don't know how long it will take, but I promise I won't leave you hanging too long."

"Yeah, I'll wait." Lucy smiled the 'Lucy smile' that always put the fire dragon slayer at ease. "After that little display, I'm pretty sure you've ruined me for other men anyway."

She stepped up and wrapped an arm around his waist while he let one of his drop over her shoulders. "Good," he said definitively. "'Cause otherwise I'd have to keep punching every guy who looks at you in the face."

Lucy snorted, feeling a rush of warmth towards her pink haired friend. "You really are such a romantic."


End file.
